Response of 2,4,6-trichlorophenol-reducing biocathode to burial depth in constructed wetland sediments

Tianming Chen; Chao Zou; Fan Chen; Ye Yuan; Jingjing Pan; Qi Zhao; Mansi Wang; Liang Qiao; Haoyi Cheng; Cheng Ding; Aijie Wang

doi:10.1016/j.jhazmat.2021.128066

Response of 2,4,6-trichlorophenol-reducing biocathode to burial depth in constructed wetland sediments

J Hazard Mater. 2022 Mar 15:426:128066. doi: 10.1016/j.jhazmat.2021.128066. Epub 2021 Dec 10.

Authors

Tianming Chen¹, Chao Zou², Fan Chen³, Ye Yuan⁴, Jingjing Pan², Qi Zhao², Mansi Wang², Liang Qiao¹, Haoyi Cheng⁵, Cheng Ding¹, Aijie Wang⁶

Affiliations

¹ School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China; Jiangsu Province Engineering Research Center of Intelligent Environmental Protection Equipment, Yancheng Institute of Technology, Yancheng 224051, China.
² School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China.
³ School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710129, China.
⁴ School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China; State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; Jiangsu Province Engineering Research Center of Intelligent Environmental Protection Equipment, Yancheng Institute of Technology, Yancheng 224051, China. Electronic address: yuanye_19840915@163.com.
⁵ State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
⁶ School of Environmental Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China; State Key Laboratory of Urban Water Resources and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China; Jiangsu Province Engineering Research Center of Intelligent Environmental Protection Equipment, Yancheng Institute of Technology, Yancheng 224051, China. Electronic address: ajwang@rcees.ac.cn.

PMID: 34915250
DOI: 10.1016/j.jhazmat.2021.128066

Abstract

Biocathode systems could be used for in-situ bioremediation of chlorophenols (CPs) in constructed wetland (CW) sediments. However, little is known regarding whether or how cathode burial depths affect the dechlorination of CPs in sediments. Here, 2,4,6-trichlorophenol (2,4,6-TCP)-dechlorinating biocathode systems were constructed under a cathode potential of - 0.7 V (vs. a saturated calomel electrode, SCE) at three different cathode burial depths (5, 10, and 15 cm). The 2,4,6-TCP removal efficiency and average transformation rate with the biocathode increased by 21.46-36.86% and 14.63-34.88% compared to those in the non-electrode groups. Deeper cathode burial depths enhanced the 2,4,6-TCP dechlorination performance. Furthermore, the oxidation-reduction potential (ORP) of the sediment decreased with sediment depth and the applied potential created a more favorable redox environment for the enrichment of functional bacteria. Deeper cathode burial depths also promoted the selective enrichment of electro-active and dechlorinating bacteria (e.g., Bacillus and Dehalobacter, respectively). The biocathode thus served as the carrier, electron source, and regulator of functional bacteria to accelerate the transformation of 2,4,6-TCP (2,4,6-TCP → 2,4-dichlorophenol → 4-chlorophenol → phenol) in sediments. These results offer insights into the effects of cathode burial depth on 2,4,6-TCP dechlorination in sediments from a redox environment and microbial community structure standpoint.

Keywords: Biocathode; Cathode burial depth; Constructed wetland sediment; Microbial community structure; Oxidation-reduction potential.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Bacteria
Burial
Chlorophenols*
Wetlands*

Substances

Chlorophenols
2,4,6-trichlorophenol